SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64900d0a1e2c5241d475be1005c0bfdb90c736dbf8151ad44df5246633841883' 
  AND token = 'jqn5JLyHIKjgmV7YseOrL5VVfBBNo+Dq08LhaY1Cu/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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