SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6be233b1240a772af8f0d1f84c6687e6047691a7aa78a97c68d677f83c230f6' 
  AND token = '0+3kutQR3drYIOvgtQQUSyujbGYXVUFxfoShG16hNJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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