SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd377baeb840baa7f5413adf2b8a9940bc0a46a21a011ba41b68d6226b4cb5998' 
  AND token = 'C+JllZylTOr1XN/zhXapgq/LI0F4ZxdSXBIYO5Vj4Xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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