SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb48ac44deb441e278e140fe0a6cd17e35bbdb9d21ce894786faf0364c2d6265' 
  AND token = 'aJ/L4nPorMN4W3kiJ+nPVV8GH9/Ph1zg3tjmuuXt5vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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