SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f559673827ea009b9b34ceeadb8fed13318be8b9728b2d12b49d5f4fbb8e6170' 
  AND token = 'r9oVzYCivYymepE12o+AVpOuTDSq05LJiH3pQlyOi8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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