SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b34129f626f62ad5de44fd9d637481bf58f5cdd062db5cb4e2fa64f4d34458f9' 
  AND token = 'JsdK/P6nmqlGnVb7737623jqlenx8B7ztAmipjoF9o4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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