SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40df7f590dec180602a4094eb29309ffd2c20201fa4d699e3021241366fc896b' 
  AND token = 'lcM4lyflDaZGycGiP89Ec0YV+8qYibRwco01ZCTkH+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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