SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c6072849ea397b8bee9c479b1d243605eba97518fb803a0ad99d3febbb3fb5d' 
  AND token = 'ZkZxOxiwo9PXNgzGRRxh1jktEggypmqGItj58UIz+uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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