SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55fbd705b7c7403c7f68fac206ed403d35af7fe7dc11bca5500208bef0534c18' 
  AND token = 'VFtsielowkumshv7eOKjA+xUyOXMC/KaiONQ5yz7BFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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