SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6e1632caf2fd8f5db6b32e3af58307c224bc919841d20653357025f98a097bb' 
  AND token = 'ujttt5uZ/vfouXZjGSsir2dy+92KEsBHBz09yzMZ/vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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