SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbde3684b2871c7167039e6cd2d584e96b2db485f8044f24a316cdc9d4e0f3a2' 
  AND token = 'BC/sFY4xKLLhmw1TXD5eUkZc25Rk5H4ZRLRIHvvlrQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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