SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be082bedf94457a692e32607fc479fd043f63975a6569b2461906378c87663e8' 
  AND token = 'osz3+ZdpLFawJW7Gvf2Ijfp5OFM+QSnKGvyLnNCdgK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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