SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '617403d927a8d68086402645bde0bb1056d5cb17b6440f365ab29de867696d6a' 
  AND token = 'O3J29QvuK20xj053oe5TNmgvUyhv9wVbEnTXqDC4ScU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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