SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '52abf870b6935c936dcfac69652b2283860cbd1515a406a873b26d10d235add5' 
  AND token = '7+pdInEiC7JVlZYAuIFfZ/gmkcR2NBFv9FvWSAbsavs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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