SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bf80a166c74d58f628b249c5706ee05ea042984db39a5d7fb0b53ef6e3670fd' 
  AND token = '1lxWlrRW8XDQ34TFHDMhIMfqePphiGaoMvs0CbyKyp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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