SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29bd005616e7911f80f8860b3db23d85befa08a791f0034b78a1769728f45f7a' 
  AND token = 'usJGqfGq24je/vkS+Nz6LbFzrptG1xqicoJvHZuRRS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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