SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f6f6be67bd57a810c0a0fc30c1bb4b1f28af9df73af3ea4093588a9f559d9cf' 
  AND token = 'FDOmzwK1qXVnB5JUxU/F/Y5W1SBDY/fQNIgPkqQJsPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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