SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '792c79001b2cdf05e3ba399395080bb8dca2d94161a4758ac7587e2c0811e3ef' 
  AND token = '1vnVPkDkvaOMcChfJvRTko0j3nQInok1PNUMuFpm2e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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