SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c4d4217d14d4cf599acae67d0762900f212dd3a73e2bf7737a6b50dfa8feea5' 
  AND token = 'l1IcZDimaxHfp0qYLryrqVr2Tpwa314i9Uc5emgsonM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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