SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8241c4f460456ce120374f8d9732747961b1e9ca02619539b36bb169a307375' 
  AND token = '95sG4vdsJpa/blrO1G3KZtkug6xGU+1ChodV4oYjNQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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