SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b65ce08910b64bc7f55c14f936f0110af323e9f2e5c627c19977d02da397ac92' 
  AND token = '+iRCFMDqb4ugQWwpVgqP+ZWNxDHbusJnt4vC4hd63Hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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