SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f402222f8bffbdfcecca79a612960489eb546b4ccaf23465385c8021649bafff' 
  AND token = 'xgQDNSfEat5QkEWX0fgFrwtAyANSCBhpP1vBfFIxE1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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