SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c42c03ef3678845def916499720e770f29e8fdcb4dfda26e02460490610ea040' 
  AND token = '0FyImHDW6Axl6E2zwZZcmY4QN68R4dnSMaI3Sv++8y8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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