SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a685cc3b6f310a74c2339274b4766291b8c4d7ca8e04803fcc45c5c6340728dd' 
  AND token = 'uaTwfOiHIxKzyjpCNDlygbjdYTerc0TvwAJkXx+d3aY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}