SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f0caa4bc1d2cc660561ae36f2e721022789e6c2ddeaf84731efc5898400f498' 
  AND token = 'oBCpPLVL2l9NkdkUP+GzwSuS403YrfVukjdQuIo2EKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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