SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e63514779a46635ef874e0e8ebaf141eb80b335ef9cfd15f939e8a6696fdc784' 
  AND token = 'vdd6eXfUvDmm4RYWvKwFOv3gVeCZPzgh+MlYcpnvWPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}