SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eee5cc993224a1f949689376f478b8027c68a876120edaff7e52a1106f3a060f' 
  AND token = 'pcv+AkrYYcpCJkhPxGETfTz3DZlcF36IjzbmDnln+/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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