SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c861249d334983300c8737b9511b6cb7ee53e3ba7002ea78e0ae541d5c09d9a9' 
  AND token = 'FbGHzjLQldpBi+K650r8vRjN29yH5eICLc4Otv9lMt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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