SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db17513f8102f493f42f242ec6b77674c0da78bbee5891b353d29232e53f3def' 
  AND token = 'eYSculhzqVafaCxKGSLD8EgPwmaMQBGKb/WtflqI/SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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