SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f02b8878ae000ebb3a827edae97a3797f1712a23f47e59be4a2b4b8bf399ccc' 
  AND token = 'YGQ2j/sCipyHJgkc7j+pdS2Uk6jQkM+GL5t7HHVkGM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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