SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e4c4dd503756559de96bc84577ede2d60b0d2bcab1998afc88873cb6495b72b' 
  AND token = 'f/NeYlCdk9HVADc3VuUYV0S9UaTK3NiqtysxKZWGEr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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