SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec2e88c2628e7fb9ccd87508625ba17cf1547e73c31b08a8287cc21cb59a5622' 
  AND token = 'p5vNc2BHTFL83hTuuZLX83cqwTsXv5Sx95QtxZq9xIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}