SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '966bcdcae04cfd58537407f738ff4b2e88aedca3117403051e43a81e901d07c2' 
  AND token = 'fgzUYuzhq1Johfll/Ux7sqG+B4cQ8+OdzOr0VRirLBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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