SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0815e78f9539a2a02277cbdd74a2f58bac1e640a68b68f58c712be1798103939' 
  AND token = 'oWMsu6iZtBH9mgSr/Kk4V6h/CWheKQF3LrszFK6bS+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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