SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bcf3e9b77c98f048ba14e6245d72de762d38c7e01838569054407e62283b5b0' 
  AND token = 'pFKbv+amZwSIhqey1+zUHNlqm4ll4+wT4Hgwe+mJsU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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