SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1bebcd6a97399502dc63195a30f0560d6c84d249b8edb5c7a6eef827e62197c' 
  AND token = 'WJH1hI5v/bT7L0qBRMGtWOggpB4aUMuvOzsUQCHXOmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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