SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '334b9e850a1c9291f9c8ec3ab9d6102a85d69ce4718d278640bd7cd6123e1302' 
  AND token = 'VQqjfovPGL465UKBqPUxBEpaIVnDyj2BZAHmv4hultg=' 
  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"
    }
  }
}