SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46fdce4e22b4443bd49f2a5fa5eed052affdac8319659b031f233c17d15c70cf' 
  AND token = 'E87Ycy9miS+s5nURu6jOPTHivgTZrBoMLjFOZdqYzqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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