SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a6fdab1697755f1c27e1a47c0d2b6eba49237afb2a4d175de97688db09f90b2' 
  AND token = 'QOYHwVLCmp1LrI9IOFez6leHOeSE6JuN+OkNndJ1Vb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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