SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23fc959415be8a2674a3ef6ca65d9f7ff569c36914c704d1d07eb4513b992b56' 
  AND token = 'oZ5nUew1UHaZ2P7qE/fxGhJFow0020xVg0LAE/YTCT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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