SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c587ccc2ae4e9b7fe0a21256c7732ca1fcb863a03275c7058a40e3c46116bc2' 
  AND token = 's+l58SakOR199fVICLqQJR5cMfq5Oi9u4lHx+Sg029I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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