SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34f8a1773542b876d2f4249732ba56170883d1e51294988aa567b1be1010dc00' 
  AND token = 'x7cZVuTnxgpplZSh+G6uIv8Ec97y6dlKc/tOG6dSY2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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