SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82d1c4b05cfc3bad79e201ac8ee3017538e79c9513b6f8b099b88bd2c0cd2439' 
  AND token = 'R+Z3tZHUqzwPWFjQjZ7QZQu0/oD6CQMUNt/yz5ZpY4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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