SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c5abd2dbd64cc1edc6dd65fb67bcfb1867f330afb08a448b931265448a51e83' 
  AND token = 'nPWxnrcDinW/GzWoSuhDHqJ+ypWxjMBjKHuPXzOeK1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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