SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '898b67a18bcf2a60292411611011f56b0c21e0deeff61ca82d05b86cc9962975' 
  AND token = 'f++5EcUBoODVkaUQQ2RZqQPsXNfmdGrzmt3K3QRpmoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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