SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8efaac379860e786f97c8c38d0354f40f545931bfb0aa9eafd64490c3bf85854' 
  AND token = 'r7JPw7UZAZFAl/wYAtWhL1RrV+c+C61nTuGJI3zbeSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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