SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd5fef81967b19b8f96858003b709d96ab5447847b29a042083a16107ba3c8e7' 
  AND token = 'yY0P8UncAYQzbrelnk6G4UQeB2qujjoJjnvB4WiZaBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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