SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e03c142d2915e0ae9170c463aef6a1825c95804b17c4a920f63bc9d757b36634' 
  AND token = 'Kz3FcmOPnNZyb8dQ7IMV1Ql5FhDB8E/pVX7/DdIaBDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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