SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68f32aafbca7512d16c473ca461cb90af69de807d1da80db088060f01a91a784' 
  AND token = 'DcLMjRQAJIdazEVmRYTceEK+CPEYNcIJ/KAcNYcRxYI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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