SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4eb3488a58bec09bc073efc5997d781408d31f22701df9165792003c773fa2c' 
  AND token = 'TN/rWzxk/OLmBSXhtlZtRWvbvbtap7XpNaMQK11RnKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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