SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdad0434634f53de8e42542212ad935d511cf3cd959efc8142e6bb48de2fcdd8' 
  AND token = 'M4sl3VAWQF+kNcUMsD//A4EHtFt1ERlPlIH11ulJC/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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