SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc80ac30fae996b0d8eacade21ff25425edbe2db9dd950608314436a5804b437' 
  AND token = 'fpbnpsFUr0NDmY5imbD718NGj6sRiOrKpHg6831W8ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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