SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9675e1988812b33ef975e21882477261757b03cd792a04119455026b1443320' 
  AND token = 'gNehgxzkjVV2m7D1MMb+BE8vQwW1y8xUaYmxKHVwcRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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