SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a41bd0158b989025a06f9fb2268cab7c349e34869148a009a181d086724580ee' 
  AND token = 'MnklwOdn7iwylnAieH6CzwXrIxM5xpfv+VlhvpZAOrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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