SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c216a893bc0b962d3ebf227095b76eba88e53259b00d5161cab2426782591d3a' 
  AND token = 'VER3sGyqhNFBCTHjQFqSpQoFMu9An7yc9e0M/0Mbf38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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