SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36ad83b094f2578cbf0bc54a132a53a3f2aaa56dccf2357a32fdfa2988bdd08b' 
  AND token = 'JvykQXRHsBLau37hB6iO7VI2prYJDuBzqPg5DC5YtDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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