SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f2185fd0097cad738ff0432311e6ffe7fe774724ccf82851978ed77868866fe' 
  AND token = 'uSN++z0G+7r24Tgi/TK1nH78X9IgPeIrWH042OQjgpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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