SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85fb2a1e15433777925809d040f4aa93821e393ddcab744008fed791bbe064e6' 
  AND token = 'Na2vjtvbZTJUVeeL9zgd42YqLfj2jhX7m6QqPxAeArE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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