SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38af9fe8b30b7088a8c578afc6f9d07d26185bbb97bf56553af506d47cf2e25f' 
  AND token = 'OalSmPfmhgR4qMcuTd1XpXkzCXKqiXfup8qDOJ+FEIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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